A report on page 1279 suggests that, for antitumor immunity, all natural killer T (NKT) cells are not created equal. Crowe and colleagues show that a subset of liver-derived NKT cells is uniquely equipped to fight off tumors.
NKT cells are innate immune cells known for their rapid production of both T helper (Th) 1 and Th2 cytokines upon stimulation. NKT cells can either promote or suppress immune responses, likely depending upon which cytokines the cells predominantly produce. Subsets of NKT cells have been identified (based on the expression of CD4) that have distinct cytokine production profiles in vitro. But whether these subsets are functionally distinct in vivo had not been tested.
In their previous work, this group had shown that NKT cells from the liver were able to combat tumors in mice. They now show that it is only CD4− NKT cells from...
